Safety switching for passenger conveyor

ABSTRACT

A passenger conveyor apparatus includes a safety switching system for sensing the conveyor condition and stopping operation thereof upon occurrence of an unsafe condition, such as a foreign object entering between the moving conveyor and the landing plate assembly therefor. An emergency stop, jog-reverse switch then permits reverse conveyor movement until the unsafe condition is terminated, and the conveyor may only be restarted thereafter by a key-operated start switch.

United States Patent 1 1 1111 3,913,723

Johnson 1 Oct. 21, 1975 [54] SAFETY SWITCHING FOR PASSENGER 3,130,3944/1964 M ct a1. 198/232 X CQNVEYOR 3,231,942 3/1966 Congelli et a1198/232 Inventor: Ernest D. Johnson, Tallmadge, Ohio WestmontIndustries, Santa Fe Springs, Calif.

Filed: July 9, 1973 Appl. No.: 377,794

Assignee:

US. Cl 198/16 R; 192/129 A; 198/232 Int. Cl. B65B 9/12 Field of Search.1 198/232, 16 R, 110;

References Cited UNlTED STATES PATENTS Dunlop .4 198/16 R Wilde et al198/110 Primary Examiner-Evon C. Blunk Assistant Examiner-Doug1as D.Watts Attorney, Agent, or Firm-Frederick K4 Lacher 15 7] ABSTRACT Apassenger conveyor apparatus includes a safety switching system forsensing the conveyor condition and stopping operation thereof uponoccurrence of an unsafe condition, such as a foreign object enteringbetween the moving conveyor and the landing plate assembly therefor Anemergency stop, jog-reverse switch then permits reverse conveyormovement until the unsafe condition is terminated, and the conveyor mayonly be restarted thereafter by a key-operated start switch.

14 Claims, 6 Drawing Figures US. Patent Oct. 21, 1975 Sheet1of33,913,723

I WWW W35 33 U.S. Patent 0a. 21, 1975 Sheet 2 of 3 3 UP RELAY /-A 43 I l44 POWER SUPPLY CQIIWTROL I MOTOR I I l 42 f oow- RELAY i 45 BRAKE RELAYBRAKE US. Patent 0a. 21, 1975 Sheet 3 of3 3,913,723

SAFETY SWITCHING FOR PASSENGER CONVEYOR This invention relates to asafety switching system for controlling a passenger conveyor, and moreparticularly to such a switching system which provides both foremergency stopping of the conveyor when a foreign object enters betweenthe landing plate and the conveyor, and permits reverse movement of theconveyor until the landing plate is clear of the foreign object.

In the past passenger conveyor systems for example, passenger conveyorwalkways and escalators of either the endless belt or moving stairwaytype, have been subject to damage due to the wedging of foreign objectssuch as a piece of clothing between the conveyor and the landing plateassembly therefor. Although close tolerances are maintained between theconveyor and the landing plate, it has been found necessary to includesafety sensing switches for stopping conveyor movement upon thedetermination of entry of a foreign object. A disadvantage of prior artsafety switching systems using such safety switches is the inability toprovide for immediate reverse conveyor movement without the assistanceof maintenance person having a special key for activating a reverseconveyor movement switch; and when the wedged object is an article ofclothing worn by a person, that person must remain in position until themaintenance person actuates the reverse switch to free the strandedrider. In some prior art passenger conveyor systems, emergency stop andreverse switches are provided for actuation without a key, but suchswitches are accessible to vandals and may be improperly used byuntrained persons causing damage to the conveyor. Also, it is advisableto have a maintenance person inspect the conveyor after an emergencystop to assure that all foreign objects are removed prior to restartingthe system in order to avoid damage to the equipment.

Accordingly, a primary object of the invention is to provide a safetyswitching system for a passenger conveyor and the like.

Another object of the invention is to provide a safety switching systemfor stopping a passenger conveyor and the like upon occurrence of anunsafe condition such as the lifting of the landing plate.

An additional object of the invention is to provide a safety switchingsystem that stops movement of the passenger conveyor and the like uponoccurrence of an unsafe condition and permits reverse operation of theconveyor until the unsafe condition is terminated.

A further object of the invention is to provide a safety switchingsystem for stopping and reversing movement of a passenger conveyor andthe like upon occurrence of an unsafe condition and for preventingrestart of the conveyor in the normal direction until the unsafecondition is terminated and a key-operated switch or the like isactuated.

Still another object of the invention is to provide a safety switchingsystem for sensing an unsafe condition, stopping and temporarilyreversing direction of movement of a passenger conveyor and the likecapable of movement in either direction.

Still an additional object of the invention is to provide a safetyswitching system for controlled operation of a passenger conveyor andthe like in which a single emergency safety switch functions both as anemergency stopping switch and as a jog-reverse switch.

Still a further object of the invention is to provide a safety switchingsystem that stops movement of a passenger conveyor and the like uponsensing an unsafe condition and provides both emergency stop andjogreverse switching functions, whereby after the passenger conveyor hasbeen stopped due to occurrence of an unsafe condition, such as thewedging of a foreign object between such conveyor and the landing platetherefor, actuation of the jog-reverse switch provides reverse movementof the conveyor until the unsafe condition is terminated at which timethe conveyor is automatically stopped.

These and other objects are realized in the instant invention whichcomprises a sensing safety switch for determining the occurrence of anunsafe condition in a passenger conveyor, an emergency stop and jogreverse switch for stopping conveyor movement at any time and forproviding reverse conveyor movement upon occurrence of a sensed unsafecondition, such reverse movement continuing until the unsafe conditionis terminated, and appropriate circuitry for facilitating adaptation ofthe safety switching system to passenger conveyors capable of operationin either direction.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described, the followingdescription and the annexed drawings setting forth in detail a certainillustrative embodiment of the invention, this being indicative,however, of but one of the various ways in which the principles of theinvention may be employed.

In the annexed drawing:

FIG. 1 is a fragmentary view in perspective of the lower end of a belttype passenger conveyor showing the 'balustrade with the handrail,conveyor, landing plate, and threshold comb;

FIG. 2 is a fragmentary schematic side elevational view of the upper endof the conveyor showing the threshold comb, landing plate and conveyoras well as the safety switch at one side of the landing plate;

FIG. 3 is a fragmentary top plan view of the threshold comb and conveyorof FIG. 2;

FIG. 4 is a section view taken along the plane of line 4-4 of FIG. 2showing the safety switches on both sides of the landing plate andthreshold comb structure;

FIG. 5 is a block diagram of the safety switching system of theinvention; and

FIG. 6 is a schematic electric circuit diagram of the system shown inFIG. 5.

Referring now in more detail to the drawings wherein like referencenumerals refer to like elements in the several figures, there is shownin FIG. I a conveyor system including a conventional moving conveyorportion 1 for passenger conveyance from one point to another. A movinghandrail 2 is mounted on a balustrade 3 and travels in the directionshown by the arrow 4 in synchronism with the moving conveyor portion I.A conventional landing plate 5 is located at the lower end of theconveyor run with a similar landing plate at the upper end thereof, suchlanding plates being positioned at close tolerance with respect to theconveyor portion I to provide a smooth transition from the moving to thestationary portions of the conveyor system. An emergency stop,jog-reverse switch 6 is located in a support casing 7 proximate thelanding plate 5 and may be actuated to stop the conveyor portion l incase of any emergency as well as to provide for reverse conveyormovement when a foreign object has become wedged between the movingconveyor portion and the landing plate 5 as will become more apparentbelow. A keyoperated start switch 8 also may be located in the casing 7or in another convenient location for starting the conveyor system,actuation of such key-operated switch being required to.start theconveyor for normal operation.

Referring now more specifically to FIGS. 2 and 4, the moving conveyorportion 1 of the conveyor system has a plurality of closely spacedlongitudinal grooves 10 in the upper load supporting surface thereofseparated by longitudinal ribs 11 integral with the conveyor portions.The conveyor belt of the moving conveyor portion I is of an endlessnature and extends around terminal pulleys 12 at opposite ends of theconveyor system for travel between the terminal ends of the conveyorrun. It should be understood, however, that the moving conveyor portionmay be of any other suitable structure, such as moving stairway platesor a smooth conveyor load supporting surface, if desired.

The stationary landing plates 5 located adjacent each end of the movingconveyor portion 1 provide generally planar surfaces onto whichpassengers and other objects are discharged from the moving conveyorportion or from which the passengers and objects move onto the conveyorportion, depending upon the direction of the movement thereof. To assistin making a smooth transition from the moving conveyor portion 1 to thestationary landing plate 5 and vice versa, a threshold comb 13 isdisposed between the moving conveyor portion and the landing plate andis carried by the forward end of the latter, although in the event thata smooth type conveyor is used, then the threshold comb arrangement maybe eliminated.

The conveyor and threshold comb arrangement are shown and described inmore detail in my US. Pat. No. 3,687,257, patented Aug. 29, I972. Thethreshold comb includes a plurality of individual comb teeth 14cooperating with the grooves 10 in the conveyor portion I and aresupported on a slider bar 15 for limited lateral movement andself-centering of the teeth within the grooves. The slider bar 15 issecurely fastened to a flange 16 on the undercarriage support 17 forlanding plate 5 and extends a short distance beyond the forward end ofthe landing plate for receipt in a generally rearwardly opening groove18 in each of the individual comb teeth 14. A downwardly depending rib20 extends transversely across the width of the slider bar 15 forreceipt in a second upwardly opening groove 21 in the teeth 14, thesliding connection between the slider bar and the teeth permitting freemovement of the teeth laterally of the former when a downward load isapplied.

Each of the comb teeth 14 has an inclined leading edge 22 with a roundedlower surface 23 extending forwardly of the main body thereof fordirecting objects upwardly to the top flat surface 24 generallyco-planar with the landing plate 5. As best seen in FIG. 4, the leadingedge 22 of each of the comb teeth 14 has a relatively narrowlongitudinally extending rib portion 25 projecting downwardly from themain body portion of the tooth and having a width somewhat less than thewidth of the grooves 10 for receipt therein without contacting the sidesthereof.

A constraining rod 26 for eliminating racking or binding of the sliderbar 15 during any lateral movement of the comb teeth 14 extends throughaligned openings in the latter and is maintained in position by snaprings 27. The vertical clearance between the leading edges 22 of thecomb teeth 14 and the adjacent surfaces of the moving conveyor portion 1should be sufficient to allow for some deflection of the comb teeth whena load is applied thereto without being forced into frictionalengagement with the tops of the conveyor ribs and the bottoms of thegrooves thereof. Preferbly, such vertical clearance is approximatelyonethirty-second inch with a maximum deflection of the comb teeth 14 andassociated support structure being no more than one-sixty-fourth inchwhen a six-hundred pound load is applied thereto.

During movement of the conveyor portion 1 toward the right as viewed atthe lower end shown in FIG. 1 and the upper end shown in FIGS. 2 through4, any objects carried on the top of the conveyor ribs 11 or within theconveyor grooves 10 will be effectively transferred from the movingconveyor portion to the flat surface of the comb teeth 14 or the landingplate 5 by the lifting action of the leading edges 22 of the comb teeth.In the event that a smooth conveyor portion is used, no comb teeth wouldbe required, and the landing plate assembly or a structure immediatelypreceding the same would be located proximate the terminal portions ofthe conveyor run in close proximity to the moving conveyor portion usingsimilar tolerances as noted above in order to provide a smoothtransition from the moving to the stationary portions of the conveyorsystem and to remove foreign objects therefrom.

Although the likelihood of an object becoming lodged in the conveyorgrooves 10 and caught between the comb teeth 14 and moving conveyorportion 1 is slight, nevertheless, in the event that such should occur,the undercarriage support 17 for the landing plate 5 and slider bar 15is pivotally connected to a fixed support 30 at each side of the landingplate 5 for effecting de-energization of the conveyor system by stoppingthe movement of the conveyor portion to prevent damage to the object andconveyor system, as will be described in more detail below. Although theswitching system would be operative using a single limit switch,preferably two limit switches 31, 32 are used for added safety in theevent that only one side of the landing plate assembly is lifted. Theextent of travel of the comb teeth 14 to actuate one of the limitswitches 31, 32 may be controlled by adjustment of respective screws 33,34 on the undercarriage support 17 which engage the limit switches.Preferably, a one-sixteenth inch vertical movement of the comb teeth 14is sufficient to trip the limit switches 31, 32 to stop the conveyormovement for safety purposes, and the total permissible verticalmovement of the comb teeth is desirably limited to approximatelyone-quarter inch by the clearance space 35 between the edges of thelanding plate 5 and the trim plates 36 at the sides of the conveyor toguard against large objects being pulled into the space between theconveyor portion 1 and the comb teeth.

For convenience of description the moving conveyor portion 1 will bereferred to hereinafter as having upper and lower ends at whichpassengers exit and enter the same, such ends representing the extremesof an escalator or moving walkway which is normally driven by one ormore drive motors 40 schematically shown in FIG. 5. The drive motors 40are controlled by respective up I and down relay systems 41, 42providing power from a power supply 43 for energizating the motor tomove the conveyor in the proper direction. A control circuit 44 includescontrols for actuating the respective up and down relay systems as wellas for providing for actuation of a brake relay and associated brakeapparatus 45, for example, an inductive brake for the motor, for rapidlystopping the latter. The up and down relay systems 41, 42 determinedrive motor and conveyor direction, for example, up and down in the caseof an inclined moving walkway or left or right in the case of ahorizontal moving walkway.

Referring now more specifically to FIG. 6, the control circuit 44 isshown receiving power from the power supply 43 through a transformer 50.The secondary winding of the transformer 50 is coupled on one sidethrough a fuse 51 to the power line 52 of the control circuit and at theother side to a ground line 53 with a control switching portion 54 andan annunciator portion 55 being coupled across the two lines. Aplurality of switches in the control switching portion 54 provide forenergization of respective up and down relays 41, 42 that control thedrive motor 40 in the proper direction, and the annunciator portion 55provides an indication of conveyor system operation.

The control switching portion 54 of the control circuit 44 includes adrive belt tension sensing switch 60 responsive to drive belt tensionand opening a circuit to the up and down relays 41, 42 when an abnormalbelt condition exists. A plurality of safety switches 61 through 64,corresponding, for example, to the limit switches 31, 32, are positionedwith the first two switches 61, 62 at the left and right sides of theupper landing plate and the latter two switches 63, 64 at the left andright sides of the lower landing plate. The emergency stop, jog-reverseswitches 65, 66, corresponding to the emergency stop switch 6, may belocated as shown, for example, in FIG. 1 at the respective upper andlower ends of the conveyor system.

The safety swtiches 61, 62 are normally in the positions shown with theswitch blades thereof contacting the fixed contacts 610, 62a, and in theevent that the upper landing plate assembly is raised, one or both ofthe respective switch blades are moved to the contacts 61b, 62b. Theupper emergency stop, jog-reverse switch 65 is a multiple contactswitch, which may be spring biased, having a first pair of normallyclosed contacts 67, 68 that complete a circuit on the line 69 providingpower to the up and down relays 41, 42 and on the line 70 to theannunciator portion 55. A second pair of normally open contacts 71, 72of the upper emergency stop, jog-reverse switch 65 may be actuated toclose a circuit to the line 73 for providing reverse drive motorenergization in the appropriate circumstance, as will become moreapparent below, and a circuit on the line 74 to the annunciator portion55. The safety switches 63, 64 and the lower emergency stop, jog-reverseswitch 66 are similar to the abovedescribed switches 61, 62, 65 andprovide corresponding circuits on the lines 75 through 78.

A direction control and starting portion 80 of the control switchingportion 54 includes a direction control switch 81 having a first contact82 for providing a circuit to the up relay 41 and a second contact 83for providing a circuit to the down relay 42.

Each of the key-operated start switches 86, 87 is spring biased to aneutral position and may be actuated in known manner to provide a bypassof, for example, the normally open contacts 84u to energize the up relay41, such energization effecting closure of the contacts 84u to provide aclosed circuit to the up relay to maintain conveyor energization andmovement when the key-operated switch is returned to its neutralposition. Normally closed lockout contacts 90a, 91d, assure that whenone of the up and down relays 41, 42 is energized, the other isincapable of energization. While the control circuit 44 may comprise theplural relays and contacts described above, it is, of course,contemplated that equivalent solid state switching arrangements may beeasily substituted therefor.

The annunciator portion 55 is energized by a transformer 92 having aprimary coupled across the line 52, 53 with a switch 93 in series withthe transformer pri mary. The switch 93 may be operated, for example, bya time delay relay responsive to power off condition of the up and downrelays 41, 42, for example, to energize the annunciator power circuitupon occurrence of such power off condition and to open such circuitshortly thereafter to avoid false annunciator signals and possibledamage to the annunciator. The secondary of the transformer 92 iscoupled through a fuse 94 to the power line 52 and through normallyclosed contacts 95a, 96d to a conventional flagdrop annunciator terminalbox 100, which has a plurality of annunciator flags 101 through forindicating conveyor operation and control circuit connections. Thus, theannunciator flag 101, when energized by the drive belt tension sensingswitch 60, indicates an abnormality in the drive belt. Energization ofthe flag 102 indicates that the upper landing plate assembly has beenraised above a preset limit. Energization of flag 103 indicates that theupper emergency stop button 65 has been pressed. Actuation of the flags104, 105 is similar to actuation of the former pair but are referencedto the lower landing plate assembly and emergency stop, jog-reverseswitch 66.

In normal operation of the conveyor system, assuming each of theswitches 60 through 66 is set as shown in FIG. 6 and the directioncontrol switch 81 is set, for example, in the up direction such that thecontacts 82 are closed and the contacts 83 are open, an actuation of oneof the upper or lower key-operated switches 86, 87 closes a circuit tothe up relay 41. Energization of the relay 41 effects closure of itscontacts to effect proper drive motor 40 energization for driving theconveyor portion 1 in the up direction. Energization of the up relay 41also effects closure of the normally open contacts 84a, so that when thekey-operated switch is released to its neutral position, the drive motor40 continues to be energized and the conveyor portion 1 continues tomove. Also, normally closed contacts 9014 are opened to assure that thedown relay 42 cannot be energized, and the normally closed contacts 9514are opened to assure no energization of the annunciator portion 55.

As the conveyor portion 1 moves in the upward direction, the comb teeth14 tend to deflect any foreign object caught in the groove 10 or ridingon the rib 11 of the conveyor belt removing such object from the movingpart of the conveyor system. If a foreign object should begin to passbeneath one or more of the comb teeth 14 a lifting effect causes thecomb teeth, slider bar 15, support surface 17, and landing plate 5 ofthe landing plate assembly to move upward opening the limit switch 31corresponding, for example, to the safety switch 61 and/or 62 shown inFIG. 6, which opens the circuit to the up relay 41 de-energizing thesame and the drive motor 40 stopping conveyor movement. At this time thecontacts 90a and 95a are again closed, the latter contacts providingpower to the annunciator 55 and the flag 102 is dropped.

A reverse movement of the conveyor portion 1 will normally clear theforeign object, whether a small article or a piece of clothing, frombeneath the comb teeth 14. Such reverse movement may be effected byactuation of the emergency stop, jog-reverse switch 65 opening contacts67, 68 and closing contacts 71, 72 to effect energization of the downrelay 42 by a circuit formed from the line 52, through the switches 60,61, 62, contacts 71 of the emergency switch 65, line 73, and contacts 90to energize the down relay 42. As long as the emergency switch 65 isactuated and the switch blade of the safety switch 62 is in connectionwith the contact 62b thereof, the conveyor portion 1 will move in thereverse direction, and when the landing plate 5 is cleared of allforeign objects and drops back into the position shown in FIGS. 2 and 4,the safety switch 62 reverts to its contact 620 opening the down relay42 energization circuit.

The conveyor system cannot again be restarted until the emergency switch65 is released and one of the keyoperated switches 86, 87 is actuated inthe proper direction to energize the appropriate up or down relay 41, 42as described above. Of course, when the conveyor portion 1 is moving inthe down direction, one or both of the safety switches 63, 64 will beopened as described above with reference to safety switch 62 when aforeign object begins to pass beneath lower landing plate assembly, andactuation of the lower emergency switch 66 will effect temporaryenergization of the up relay 41 until the lower landing plate iscleared.

Thus, the provision of the emergency stop, jogreverse switches 65, 66 atthe terminal portions of the conveyor system permits any one person whohas become stranded on the conveyor by having an article of clothingcaught under one or more of the comb teeth 14 to be extricated therefromby any person actuating the appropriate emergency switch 65, 66. Sincecontinued reverse conveyor movement is undesirable for well knownreasons, the conveyor system automatically stops after the foreignobject is cleared from beneath the comb teeth and cannot be restarteduntil a maintenance person with the appropriate key actuates one of thekey-operated start switches 86, 87, affording the maintenance person anopportunity to determine that the conveyor system is safe for continuedoperation prior to starting the same.

While certain representative embodiments and details have been shown forthe purpose of illustrating the invention, it will be apparent to thoseskilled in the art that various changes and modifications may be madetherein without departing from the spirit or scope of the invention.

I, therefore, particularly point out and claim as my invention:

1. A safety switching system for passenger conveyors and the like,comprising means responsive to the condition of a conveyor for stoppingthe same upon occurrence of an unsafe condition, said means responsivecomprising switch means for normally establishing a first circuit forconveyor energization to effect movement thereof in a first directionand for establishing upon occurrence of such unsafe condition a secondcircuit for conveyor energization to effect movement thereof in areverse direction, and selectively operable means coupled to said meansresponsive for restarting said conveyor in reverse direction after saidmeans responsive has sensed occurrence of such unsafe condition.

2. A safety switching system for passenger conveyors and the like as setforth in claim I, wherein said switch means comprises plural switchmeans positioned proximate respective ends of said conveyor.

3. A safety switching system for passenger conveyors and the like as setforth in claim 1, wherein said conveyor comprises a moving part and anormally relatively stationary part, and said switch means beingpositioned proximate said stationary part and being responsive to aforeign object entering between said stationary part and said movingpart.

4. A safety switching system for passenger conveyors and the like as setforth in claim 3, wherein said moving part comprises a moving conveyorportion, and said stationary part comprises respective landing plateassemblies positioned at opposite ends of said conveyor portion, saidswitch means comprising first and second switch means positioned onopposite sides of a first one of said landing plate assemblies and thirdand fourth switch means positioned on opposite sides of the other one ofsaid landing plate assemblies, said switch means being responsive to alifting of said respective landing plate assemblies for stoppingconveyor movement upon sensing such lifting.

5. A safety switching system for passenger conveyors and the like as setforth in claim 4, wherein said means coupled comprises emergency switchmeans for controlling conveyor energization and movement thereof, saidemergency switch means being connected for interrupting conveyormovement upon actuation during normal operation of said conveyor.

6. A safety switching system for passenger conveyors and the like as setforth in claim 1, wherein said means coupled comprises emergency switchmeans for controlling conveyor energization, said emergency switch meansbeing connected for interrupting conveyor movement upon actuation duringnormal operation of said conveyor.

7. A safety switching system for passenger conveyors and the like as setforth in claim 6, further comprising key-operated switch means coupledto both said means responsive and said means coupled for effectingstarting of said conveyor in said first direction.

8. A safety switching system for passenger conveyors and the like as setforth in claim 7, further comprising annunciator means coupled to saidemergency switch means for indicating operative condition of saidconveyor.

9. A safety switching system for passenger conveyors and the like as setforth in claim 1, wherein said means responsive stops reverse conveyormovement upon sensing termination of such unsafe condition.

10. A safety switching system for passenger conveyors and the likecomprising means responsive to the condition of a conveyor for stoppingthe same upon occurrence of an unsafe condition, said means responsivecomprising switch means for normally establishing a first circuit forconveyor energization to effect movement thereof in a first directionand for establishing upon occurrence of such unsafe condition a secondcircuit for conveyor energization to effect movement thereof in areverse direction, means coupled to said means responsive for restartingsaid conveyor in reverse direction after said means responsive hassensed occurrence of such unsafe condition, said means coupledcomprising emergency switch means for controlling conveyor energization,said emergency switch means being connected for interrupting conveyormovement upon actuation during normal operation of said conveyor, andfurther comprising first and second relay means for effectingenergization of said conveyor respectively in said first and reversedirections, said relay means being coupled to said emergency switchmeans, whereby said emergency switch means normally provides one circuitfor energizing said first relay to effect conveyor movement in saidfirst direction and interrupting said one circuit upon actuation thereofto de-energize said first relay means stopping such normal conveyormovement, said emergency switch means providing upon actuation anothercircuit for energizing said second relay means to effect conveyorreverse movement when said means responsive has sensed the occurrence ofsuch unsafe condition.

11. A safety switching system for passenger conveyors and the like asset forth in claim 10, further comprising first and second pairs ofnormally closed contacts, each such pair being coupled in series with arespective one of said first and second relay means and controlled bythe other one of such relay means, whereby upon energization of one ofsaid relay means the other of said relay means is disabled fromenergization.

12. A safety switching system for passenger conveyors and the like asset forth in claim 10, further comprising first and second normally opencontact means respectively coupled in said one and another circuits inseries with said first and second relay means and controlled thereby,first and second normally open start switch means respectively coupledacross said first and second normally open contacts for providing uponactuation a short circuit across such contacts to effect energization ofa respective one of said first and second relay means, whereby actuationof one of said start switch means effects energization of the respectiveones of said first and second relay means which in turn closes itsassociated contacts to continue energization thereof upon release ofsaid start switch means.

13. A safety switching system for passenger conveyors and the like asset forth in claim 12, wherein said start switch means compriseskey-operated switch means.

14. A safety switching system for passenger conveyors and the like asset forth in claim 13. wherein said conveyor comprises a moving conveyorportion adapt able for movement in either of two directions and respective first and second landing plate assemblies positioned at therespective ends of the former, said switch means being positioned withrespect to said first and second landing plate assemblies to detect thelifting thereof, and said emergency switch means comprises a pluralityof the same, one located proximate each end of said moving conveyorportion.

1. A safety switching system for passenger conveyors and the like,comprising means responsive to the condition of a conveyor for stoppingthe same upon occurrence of an unsafe condition, said means responsivecomprising switch means for normally establishing a first circuit forconveyor energization to effect movement thereof in a first directionand for establishing upon occurrence of such unsafe condition a secondcircuit for conveyor energization to effect movement thereof in areverse direction, and selectively operable means coupled to said meansresponsive for restarting said conveyor in reverse direction after saidmeans responsive has sensed occurrence of such unsafe condition.
 2. Asafety switching system for passenger conveyors and the like as setforth in claim 1, wherein said switch means comprises plural switchmeans positioned proximate respective ends of said conveyor.
 3. A safetyswitching system for passenger conveyors and the like as set forth inclaim 1, wherein said conveyor comprises a moving part and a normallyrelatively stationary part, and said switch means being positionedproximate said stationary part and being responsive to a foreign objectentering between said stationary part and said moving part.
 4. A safetyswitching system for passenger conveyors and the like as set forth inclaim 3, wherein said moving part comprises a moving conveyor portion,and said stationary part comprises respective landing plate assembliespositioned at opposite ends of said conveyor portion, said switch meanscomprising first and second switch means positioned on opposite sides ofa first one of said landing plate assemblies and third and fourth switchmeans positioned on opposite sides of the other one of said landingplate assemblies, said switch means being responsive to a lifting ofsaid respective landing plate assemblies for stopping conveyor movementupon sensing such lifting.
 5. A safety switching system for passengerconveyors and the like as set forth in claim 4, wherein said meanscoupled comprises emergency switch means for controlling conveyorenergization and movement thereof, said emergency switch means beingconnected for interrupting conveyor movement upon actuation duringnormal operation of said conveyor.
 6. A safety switching system forpassenger conveyors and the like as set forth in claim 1, wherein saidmeans coupled comprises emergency switch means for controlling conveyorenergization, said emergency switch means being connected forinterrupting conveyor movement upon actuation during normal operation ofsaid conveyor.
 7. A safety switching system for passenger conveyors andthe like as set forth in claim 6, further comprising key-operated switchmeans coupled to both said means responsive and said means coupled foreffecting starting of said conveyor in said first direction.
 8. A safetyswitching system for passenger conveyors and the like as set forth inclaim 7, further comprising annunciator means coupled to said emergencyswitch means for indicating operative condition of said conveyor.
 9. Asafety switching system for passenger convEyors and the like as setforth in claim 1, wherein said means responsive stops reverse conveyormovement upon sensing termination of such unsafe condition.
 10. A safetyswitching system for passenger conveyors and the like comprising meansresponsive to the condition of a conveyor for stopping the same uponoccurrence of an unsafe condition, said means responsive comprisingswitch means for normally establishing a first circuit for conveyorenergization to effect movement thereof in a first direction and forestablishing upon occurrence of such unsafe condition a second circuitfor conveyor energization to effect movement thereof in a reversedirection, means coupled to said means responsive for restarting saidconveyor in reverse direction after said means responsive has sensedoccurrence of such unsafe condition, said means coupled comprisingemergency switch means for controlling conveyor energization, saidemergency switch means being connected for interrupting conveyormovement upon actuation during normal operation of said conveyor, andfurther comprising first and second relay means for effectingenergization of said conveyor respectively in said first and reversedirections, said relay means being coupled to said emergency switchmeans, whereby said emergency switch means normally provides one circuitfor energizing said first relay to effect conveyor movement in saidfirst direction and interrupting said one circuit upon actuation thereofto de-energize said first relay means stopping such normal conveyormovement, said emergency switch means providing upon actuation anothercircuit for energizing said second relay means to effect conveyorreverse movement when said means responsive has sensed the occurrence ofsuch unsafe condition.
 11. A safety switching system for passengerconveyors and the like as set forth in claim 10, further comprisingfirst and second pairs of normally closed contacts, each such pair beingcoupled in series with a respective one of said first and second relaymeans and controlled by the other one of such relay means, whereby uponenergization of one of said relay means the other of said relay means isdisabled from energization.
 12. A safety switching system for passengerconveyors and the like as set forth in claim 10, further comprisingfirst and second normally open contact means respectively coupled insaid one and another circuits in series with said first and second relaymeans and controlled thereby, first and second normally open startswitch means respectively coupled across said first and second normallyopen contacts for providing upon actuation a short circuit across suchcontacts to effect energization of a respective one of said first andsecond relay means, whereby actuation of one of said start switch meanseffects energization of the respective ones of said first and secondrelay means which in turn closes its associated contacts to continueenergization thereof upon release of said start switch means.
 13. Asafety switching system for passenger conveyors and the like as setforth in claim 12, wherein said start switch means compriseskey-operated switch means.
 14. A safety switching system for passengerconveyors and the like as set forth in claim
 13. wherein said conveyorcomprises a moving conveyor portion adaptable for movement in either oftwo directions and respective first and second landing plate assembliespositioned at the respective ends of the former, said switch means beingpositioned with respect to said first and second landing plateassemblies to detect the lifting thereof, and said emergency switchmeans comprises a plurality of the same, one located proximate each endof said moving conveyor portion.